U.S. Pat. No. 3,947,571 relates to the use of a microencapsulated oil in lipstick. Moisture applied to the lips after the lipstick has been applied results in a sustained release of oil from the capsules thus imparting a shiny "wet" look to the lips. This patent does not suggest microencapsulating pigment per se, nor does it suggest activating an encapsulated or dormant pigment by effecting rupture of the microcapsules via applied shear forces in order to achieve a "long wearing" affect.
U.S. Pat. No. 4,752,496 relates to the microencapsulation of "never dry" or paste cosmetics using the well known coacervation technique. After encapsulation the "greasy" cosmetic is applied to a substrate and subsequently overlaid with a film forming agent. The substrate may be used as samples capable of being distributed to consumers through the mail, or on inserts in magazines. Although this patent does suggest microencapsulating a "lipstick" formulation, it does not disclose nor suggest microencapsulation of a pigment in a cosmetic formulation (e.g. lipstick) for the purpose of rendering it dormant so that it subsequently may be activated to achieve a "long wearing" affect.
An Information Bulletin published by Dow Corning (Form No. 24-550-88) entitled "Information About Specialty Copolymers" describes a highly cross-linked polymethacrylate copolymer in the form of a fine particle-sized, freely flowing powder which may be used to absorb various liquid systems both volatile and non-volatile used in cosmetic formulations. The Information Bulletin states that the Dow Corning polymer, sold under the designation POLYTRAP Q5-6603, may be spread into a thin film on a surface, such as rubbing on the skin, to cause the absorbed fluids to come into contact with such surface. The Dow Corning Information Bulletin however, fails to suggest loading the polymethacrylate copolymer with a pigment so that the latter may be rendered dormant until "activated" or released on a sustained basis for renewing the color in a cosmetic formulation and achieving a "long wearing" affect.
Past attempts to provide acceptable cosmetic products having pigmented solid particles which may be activated or released on a sustained basis by the application of shear forces thereby giving a renewed color intensity or "long wearing" look have not been successful. When pigments were microencapsulated and placed directly into a cosmetic base, it was found that the microcapsules felt "gritty and hard" on the skin, thus rendering the composition unacceptable as a cosmetic product. Attempts to ameliorate this undesirable condition by mixing the solid particles with oils or emollients of various types to form a dispersion also resulted in failure by yielding microcapsules that were fragile, and thus too easily rupturable during handling, or pigment concentrations insufficient to give the desired renewed color intensity. When pigment was added to fine particle-size agglomerated powders combined with a cosmetic vehicle or base and then rubbed into the skin, intensification of color was inadequate to provide a "long wearing" affect.
These disadvantages were overcome by the present invention when it was discovered that in a first form cosmetically acceptable compositions may be produced having microencapsulated pigmented solid particles by forming a dispersion of the pigment in a hydrophobic, non-volatile, low viscosity liquid carrier; coacervating the dispersion to yield microcapsules in the form of a stable, freely flowing, dry powder; and then incorporating the microcapsules in a compatible anhydrous base or vehicle. In a second or alternatively preferred form of the invention, it was discovered that the pigment could be loaded onto a fine particle-size, high surface area, solid substrate and then coated with an adherring oil or outer film to entrap the pigment on the substrate. When the resulting cosmetic compositions were applied to the skin and rubbed or otherwise subjected to shear forces, the microcapsules and/or entrapping substrate particles were readily ruptured or otherwise mechanically distorted thereby releasing their intensely colored pigment and giving the compositions' color or shade a perceptible "long wearing" look.